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Living on mostly 12v and reducing power


DavidH
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Will an auto-transformer be needed in a supportable solution, for simultaneous 120v split phase & 240v on a GS 6K, to tie the neutral of a split-phase? (I am still trying to be sure on this point... some other vendor solutions require this

 

Do not use an  autotransformer  because it max out at 5000 watts  .   See youtube  review on Gowatt using   autotransformer to make 240vac and  surge exceed  5000 watt  and  the  neutral will be disconnected  and  the ground wire  will become  the neutral wire and a person can be electrocuted or the house catch on fire .    Gowatt  is HF inverter  and not true split-phase .    

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  • 1 month later...
On 10/7/2021 at 5:39 PM, Sid Genetry Solar said:

95% load anyway.  6000W / 240v = 25A.  Remember that the LRA rating is <1sec, so it won't have any bearing on system capacity (i.e. heat limits), but rather entirely an absolute power limit.  No matter what kind of "soft start" you come up with, you will not be able to reduce the startup surge to the FLA rating...that's just how synchronous AC motors work.

Well, 240v * 50A = 12,000W, so not exactly. 

It seemed Micro Air Soft Start Kit

  • Reduces peak from 70Ah to 30Ah
  • Reduces avg from 12Ah to 9Ah

https://youtu.be/uowVMYuPs-U

I saw it on YouTube, must be true! Lol! :-)

On 10/7/2021 at 5:39 PM, Sid Genetry Solar said:

GS inverters as of yet do not have a solar charge controller built in.  However, they can charge from AC input--though the AC input will have to be able to power the entire load in addition to the battery charge power requirements, in order to charge the batteries.

Would optimizers on the panels provide a constant voltage, then I could plug the DC lines into the battery input, use diodes to keep the battery isolated, use a separate battery charging circuit?

On 10/7/2021 at 5:39 PM, Sid Genetry Solar said:

Curious then if you have grid-tie inverters already picked out...if so, what are they?

I have a temporary source for used 61v panels used USA built panels. I was designing a retractable black pipe racking system.

I had my heart set on 2x $440 discontinued Delta H6 hybrid inverters, that would only run in grid tied mode (due to crippled software), and was considering used SPIM08HP batteries for ~600v DC battery assembly (your earlier messages about higher voltage impacted me 🙂 ) (The delta looked like it would shut off with frequency shift, while it had no real intelligence besides grid tie & charge batteries & dump power from batteries when sunlight was too low. (It looked like the input panel could set the range for frequency shift shutoff, so I was ready to ask you if the GS could gradually shift to disable multiple grid tied inverters progressively, one at a time 🙂 ) 

The Delta sold out a few days back, shortly before I was able to finish the design & pull the trigger on everything.

No more Delta grid tie blew up my design.

Back to ground zero.

Every time I turn around, I am unhappy with what I see.

I may considering returning to a wall of EGO batteries for a GS to run as a UPS. (I still need to design a large 56v interconnect with isolations.)

I am considering building my own solar panel optimizers, to dial each solar panel DC output voltage to what I choose (61v DC solar panels leave me with too few inexpensive options, but close enough to an EGO battery wall.)

I contemplated DIY grid tie circuits, at whatever voltage I dial in. 😞  

I thought about 120v or 240v DC solar input, convert to a square wave, trim to a stepped sine wave… then I concluded I did not want to be GS since I had already watched all your videos! 🙂 

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I am considering building my own solar panel optimizers, to dial each solar panel DC output voltage to what I choose (61v DC solar panels leave me with too few inexpensive options, but close enough to an EGO battery wall.)

Are your 61v DC solar panels  made by Sunpower ?     All my  solar panel are  61v Sunpower which  leave little option  but  MSB   60amp  119 dollars  will  work  to run my powerjack with 16s battery .   

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  On 6/29/2021 at 9:11 PM, DavidH said:

My question was just before the gs12 test. I was hoping for a good result on the gs12.

I'm not quitting on the 12kw.  Have 3 things to try...should be able to get it working one way or another!  For one, FET crosstalk/drive issues are the bulk of it...need to figure out how to get the best drive signals on the gate without punching the gates out with overvoltage...AND limit the maximum throttle.  I recall that @Ben managed to explosively blow out a set of FETs with no load on the inverter...by connecting the AC output wires up wrong.  That tells me that these high-wattage transformers won't accept a square wave input...they'll basically dead-short the battery and blow the FETs out.  So I need to determine what a safe maximum throttle is...and go 20% less than that.

I  replace  the 15kw powerjack  long mainboard  with the short mini mainboard like in the 20kw powerjack .   The  long  trace inside the long mainboard  shorted by crosstalk  at high surge will blow up all the FETs and LF driver .  I  fix the short and use the damage mainboard  for 6  more  capacitors  connected to the  4 on the mini mainboard  so total  of 10  100v 10000uf  capacitors  .    Be sure to precharge the  capacitor  before connecting  battery .   The new  AMG powerjack has a  mini mini mainboard  where the trace inside the mainboard  is so short that there is  no crosstalk  .  

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4 hours ago, DavidH said:

so I was ready to ask you if the GS could gradually shift to disable multiple grid tied inverters progressively, one at a time 🙂 ) 

Sure can, out of the box.  While I have yet to test this function on an actual grid-tied setup, it IS written.  If the inverter detects reverse power flow on the AC Output sensor (beyond a threshold), it'll start to shift the frequency up over 2-3 seconds up to 62Hz.  If the reverse power is still present at that point, it'll shut down with a GTM Regulate Fail error.  (Grid Tie Master regulation fail--"I tried to turn it down, but it won't turn off!")

The goal of this would be to "throttle down" a smart grid-tie inverter to a point...then if power starts flowing forwards again, the frequency shift will start to come back down.

 

4 hours ago, DavidH said:

Would optimizers on the panels provide a constant voltage, then I could plug the DC lines into the battery input, use diodes to keep the battery isolated, use a separate battery charging circuit?

I'm not familiar with "optimizers", could you provide more details?  (Part number?)

You could use diodes alright, but prepare to heatsink 'em good, as they'll get HOT under full load!  6kw @ 80% and 48v is 150A.

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https://www.mcelectrical.com.au/tigo-energy-solar-panel-optimisers/

I don't think they are really appropriate for feeding into something that expects some form of regulated input, including actual battery charging.  That's not their intent.  Sure some types attempt to provide a constant voltage from the panels for loads that aren't MPPT based, but others attempt to be a better bypass than a diode (not that hard really!) to avoid restricting current through the entire array and don't make any attempt to control the panel output voltage.

Part of the reason these things exist at all is down to really bad MPPT algos in inverters and by bad I mean they don't really MPPT.  If you want an example, Dave of eevblog youtube fame did a story about his older system that suffered quite badly from minor shading,  The ultimate problem there was that the tracker in his inverter couldn't cope with Vmp reduction from the array when the bypass diodes came into effect so when the minor shading happened his inverter kept the array voltage well above Vmp and output power suffered significantly.

This wasn't a cheap junk inverter either, it's a SMA.  A firmware update would address the problem.  SMA announced the fix as a special shadefix algo rather than simply a proper MPPT algo.  :classic_rolleyes:

Use a decent MPPT charger with a non-dumb algo that can support no-battery operation (a lot can, makeskyblue can't) and you'll be most of the way home but if you do have shading issues and they are causing problem fix them with Mr Chain Saw if possible.

Edited by TheButcher
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On 11/21/2021 at 5:00 AM, dickson said:

Are your 61v DC solar panels  made by Sunpower ?     All my  solar panel are  61v Sunpower which  leave little option  but  MSB   60amp  119 dollars  will  work  to run my powerjack with 16s battery .   

The used panels I am considering are frameless 145w panels: 61v mppt with 80v open circuit voltage. 
https://sunnycalsolar.com/wp-content/uploads/2018/06/Stion-Frameless-STL-Datasheet.pdf

I have not made the purchase yet, since I am still trying to identify all the pieces I need. 😞 

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On 11/21/2021 at 8:32 AM, Sid Genetry Solar said:

While I have yet to test this function on an actual grid-tied setup, it IS written.  If the inverter detects reverse power flow on the AC Output sensor (beyond a threshold), it'll start to shift the frequency up over 2-3 seconds up to 62Hz.  If the reverse power is still present at that point, it'll shut down with a GTM Regulate Fail error.  (Grid Tie Master regulation fail--"I tried to turn it down, but it won't turn off!")

Well done with your efforts!

The more I read on this topic of Grid Tie & a main Inverter, the clearer it becomes that the main inverter needs a big battery to sync the power from the Grid Ties!

The only other options seem to be: 1) shut off Grid Ties; 2) add some heat & fan & incandescent light bulbs to sink excess Grid Tie power; 3) shut off the inverter; 4) allow main inverter to feed electrical grid: 5) allow main inverter to blow up 

A simple synchronous buck-boost converter on some panel in parallel to high DC voltage to a gateway feeding a main inverter seems like an elegant design, but finding the components for 80Voc panels with 61Vmp seems nearly impossible. Almost like I have to design it, myself. (If I owned the panels already, I would likely have started designing.)

The racking is looking like a massive cost, as well, since I don’t want to pierce my roof & don’t have the land to build a whole solar structure far from my home.

Batteries drop every day, it seems. I have some favorites, which I may execute on in the next couple days, not only because of cost, but because of massive current output. The problem is BMS limited output current, which brings me to maybe just using a balancer above 50v on previously matched & balanced cells.

To use GS without UL / ETL, when not officially off-grid, I guess I basically need an external auto transfer switch? Or maybe off-grid parallel circuits around the house?

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16 minutes ago, dickson said:

The used panels I am considering are frameless 145w panels: 61v mppt with 80v open circuit voltage

There are lot  of panel over 300 watts  but few  over 60 VOC .   Sunpower make good panels .

 

yes, the 145W panels @80Voc are smaller & odd, but I can get them with mounting hardware for $40 each, free shipping, but wow have they cost me time in figuring out how to use them! LOL!

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 I can get them with mounting hardware for $40 each, free shipping, but wow have they cost me time in figuring out how to use them! LOL!

I  started with  2 solar panels  to  4 battery to 48v powerjack to find  the cost .   The cost for  wires  and  MPPT  solar controller  and  fuse and breaker box  is way more than I  first  design  the system .   Once I  started  I  find that the cost  keep going up  with  building  the system  big and  bigger  and  now no end in  sight  .   I   can only at the most run offgrid  for 16 hours  in the winter  and 6 hours in the summer .   It is  almost  impossible  to plan  when  DIY  with  used parts .  

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